1. Field of the Invention
An ophthalmic endothelial microscope assembly capable of optical observation through a sighting assembly aligned with an objective lens simultaneously to gauging or determination of the thickness dimension of the cornea portion of the eye through manipulation of the focusing assembly to accomplish proper and required observation of the eye.
2. Description of the Prior Art
Medical science has for some years been capable of performing corneal transplants from donor material into the body of a living patient. For efficient accomplishment of this procedure human corneal donor material is required to be examined in order to determine generally its fitness for transplant. Among certain factors specifically required for examination is the thickness dimension of the cornea.
The examination of human corneal donor material before grafting has been limited generally to slit-lamp observation. The presence of endothelial folds and cornea guttata has been the criteria for deciding whether or not to use a cornea for transplantation. Staining with the vital dyes, trypan blue and lissamine green, have been suggested as more accurate methods for assessing donor endothelial viability. These tests, however, have generally been performed on the excised donor button and may require irrigation of the endothelium.
An ophthalmic endothelial microscope assembly developed by Dr. David Maurice, PhD, has previously offered a new means of critical examination of corneal donor material while the globe remains intact. With this structure corneal thickness and thickness of the individual layers was capable of measurement to within generally desirable ranges at various points along the cornea. Advantages of this prior art system includes examination of the cornea portions while the globe is intact thereby eliminating the need of exposure of the corneal endothelium or the handling or washing thereof.
However, this prior art structure of Maurice was generally limited to observation and examination of the eye after removal from the human or animal donor.
Subsequent to the introduction of the Maurice ophthalmic endothelial microscope assembly, structural modifications were made to this structure which allowed for the observation and photographing of the corneal endothelium in live patients. The later developed method was suitable for animal experimentation and for diagnostic observation in clinical research in humans. While this apparatus described a method for the direct microscopic visualization of the corneal endothelium in vivo and further provided for the recording of the image photographically, certain means contained in the structure did not accomplish maximum efficiency relative to capabilities for accurately gauging the thicknes of the cornea.
Accordingly, there is a recognized need in this particular area of medical science for the accurate examination, observation and more specifically measurement of the thickness of the corneal emdothelium. This measurement, as generally set forth above, is requisite in the determination of proper condition of the cornea to insure that the endothelium is free from those morphological changes in the cells of the endothelium associated with age, inflammation and ocular disease. Previous to the invention described herein information correlating this morphological changes with abnormal physiological function in live patients has been limited.